Immobilizer preform, immobilizer device, and method of forming the same

ABSTRACT

Aspects of the invention include preforms used to be formed into an immobilizer for use with a patient. The preform includes a preform member that is formed from a thermoplastic material and a filler material. The preform member is relatively rigid at a first temperature and formable at an elevated second temperature. The preform member is opaque at the first and second temperatures. The preform also includes at least one indicator associated with the preform member. The at least one indicator is formed from a thermoplastic material and is opaque at the first temperature and translucent at the second temperature. The at least one indicator can provide a visual indication of readiness to form the preform into the immobilizer upon heating the preform member to the second temperature at which the indicator is translucent.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.14/134,685, filed Dec. 19, 2013, which claims priority of ProvisionalApplication No. 61/746,931 (“Low Temperature Thermoplastic With UnfilledSections Such That Temperature And Readiness To Mold Can Be Monitored”)filed on Dec. 28, 2012, the entire disclosures of which are incorporatedherein by reference in their entirety for all purposes.

BACKGROUND OF THE INVENTION

There is a growing need for improved devices that can immobilizepatients or patient anatomies. For example, thermoplastic sheets areknown and used as patient immobilizers in radiation therapy to reduce orprevent movement of patient anatomies during therapy. Such sheets areheated to become formable, formed over a part of a patient's anatomy,and then cooled to harden, thereby immobilizing the patient or patient'sanatomy for the treatment therapy.

Despite developments that have been made in connection with suchdevices, there remains a need for improved patient immobilizers as wellas improved methods and processes for immobilizing patients in terms ofat least one of cost control, enhanced performance, and ease of use.

SUMMARY OF THE INVENTION

Aspects of the invention include preforms used to be formed into animmobilizer for use with a patient. The preform includes a preformmember that is formed from a thermoplastic material and a fillermaterial. The preform member is relatively rigid at a first temperatureand formable at an elevated second temperature. The preform member isopaque at the first and second temperatures. The preform also includesat least one indicator associated with the preform member. The indicatorhas an appearance at the first temperature and a different appearance atthe second temperature, wherein the indicator provides a visualindication of readiness to form the preform into the immobilizer uponheating the preform member to the second temperature at which theindicator has the different appearance. For example, the at least oneindicator is optionally formed from a thermoplastic material and isopaque at the first temperature and translucent at the secondtemperature. When the at least one indicator is formed from athermoplastic material that is opaque at the first temperature andtranslucent at the second temperature, the at least one indicatorprovides a visual indication of readiness to form the preform into theimmobilizer upon heating the preform member to the second temperature atwhich the indicator is translucent. Alternatively, the at least oneindicator is optionally formed from a material including a thermochromicdye or other color indicator that can provide a different appearance atthe second temperature.

Aspects of the invention also include methods of preparing a preform tobe formed into an immobilizer for a patient. A preform member of thepreform is heated from a first temperature at which the preform memberis relatively rigid to a second temperature at which the preform membercan be molded. The preform member includes a thermoplastic material anda filler material and is opaque at the first and second temperatures. Anindicator associated with the preform member is monitored during theheating of the preform member. The indicator has an appearance at thefirst temperature and a different appearance at the second temperature,wherein the indicator provides a visual indication of readiness to formthe preform into the immobilizer upon heating the preform member to thesecond temperature at which the indicator has the different appearance.The indicator is optionally formed from a thermoplastic material that isopaque at the first temperature and translucent at the secondtemperature. When the indicator is formed from a thermoplastic materialthat is opaque at the first temperature and translucent at the secondtemperature, the heating of the preform member is terminated after theindicator becomes translucent, providing a visual indication of thereadiness to form the preform into the immobilizer. Alternatively, theat least one indicator is optionally formed from a material including athermochromic dye or other color indicator that can provide a differentappearance at the second temperature. The heating of the preform memberis terminated after the indicator has the different appearance,providing a visual indication of the readiness to form the preform intothe immobilizer.

Aspects of the invention also include immobilization devices withmultiple sections formed from polycaprolactone low temperaturethermoplastic. The immobilization device includes at least one preformsection that does not become translucent when heated to its meltingpoint, the preform section being formed from the polycaprolactone lowtemperature thermoplastic and a filler material. The immobilizationdevice also includes at least one indicator section. The indicatorsection has an appearance at a first temperature and a differentappearance at a second temperature, wherein the indicator sectionprovides a visual indication of readiness to form the preform sectioninto the immobilization device upon heating the preform section to thesecond temperature at which the indicator section has the differentappearance. For example, the indicator section optionally becomestranslucent when heated to its melting point. Alternatively, the atleast one indicator section is optionally formed from a materialincluding a thermochromic dye or other color indicator that can providea different appearance at the second temperature.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is best understood from the following detailed descriptionwhen read in connection with the accompanying drawings, with likeelements having the same reference numerals. When a plurality of similarelements is present, a single reference numeral may be assigned to theplurality of similar elements with a small letter designation referringto specific elements. Included in the drawings are the followingfigures:

FIG. 1 is a schematic diagram depicting an embodiment of a preformaccording to aspects of the invention;

FIGS. 2 and 3 depict various applications of a preform being formed intoan immobilizer for use with a patient's anatomy according to aspects ofthe invention;

FIG. 4 is a representation of an embodiment of a preform member inaccordance with aspects of the invention;

FIG. 5 is a top view of an embodiment of a preform in accordance withaspects of the invention;

FIGS. 6A and 6B illustrate an embodiment of a preform member andindicator according to aspects of the invention.

FIGS. 7-9D are top views of embodiments of preforms with indicators invarious positions according to aspects of the invention;

FIGS. 10A-10C are cross-sectional side views of embodiments of preformmembers and indicators in accordance with aspects of the invention;

FIGS. 11A and 11B are isometric views of portions of an embodiment of apreform with an indicator and indicium according to aspects of theinvention; and

FIGS. 12A-12C are cross-sectional side views illustrating steps of anembodiment of a method for disposing an indicium within an indicator inaccordance with aspects of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Although the invention is illustrated and described herein withreference to specific embodiments, the invention is not intended to belimited to the details shown. Rather, various modifications may be madein the details within the scope and range of equivalents of the claimsand without departing from the invention.

Referring to the figures generally, the invention provides preforms,such as preforms 1, 2, 3, and 4, used to be formed into an immobilizerfor use with a patient. The preform includes a preform member, such aspreform members 10, 30, 50, and 70, that is formed from a thermoplasticmaterial and a filler material. The preform member is relatively rigidat a first temperature and formable at an elevated second temperature.The preform member is opaque at the first and second temperatures. Thepreform also includes at least one indicator, such as indicators 12, 26,34, 36, 38, 52, 62, and 72, associated with the preform member. Theindicator has an appearance at the first temperature and a differentappearance at the second temperature, wherein the indicator provides avisual indication of readiness to form the preform into the immobilizerupon heating the preform member to the second temperature at which theindicator has the different appearance. For example, the at least oneindicator is optionally formed from a thermoplastic material that isopaque at the first temperature and translucent at the secondtemperature. When the at least one indicator is formed from athermoplastic material that is opaque at the first temperature andtranslucent at the second temperature, the at least one indicatorprovides a visual indication of readiness to form the preform into theimmobilizer upon heating the preform member to the second temperature atwhich the indicator is translucent. Alternatively, the at least oneindicator is optionally formed from a material including a thermochromicdye or other color indicator that can provide a different appearance atthe second temperature.

The preform member can be opaque or substantially opaque at the firstand second temperatures. For example, the preform member can havesubstantially the same degree of opacity or imperviousness to light atthe first and second temperatures. In contrast, the indicator can beopaque or substantially opaque at the first temperature and translucentor substantially translucent at the second temperature. For example, theindicator can have a lesser degree of opacity or imperviousness to lightat the second temperature as compared to at the first temperature, andthe indicator can have a greater degree of translucence at the secondtemperature as compared to at the first temperature.

The preform may include a frame member, such as frame member 24, 32, and60, associated with the preform member, with the indicator being coupledto at least one of the frame member or the preform member. The indicatorcan be positioned on at least one of a surface portion of the framemember, if the preform includes a frame member, or a surface portion ofthe preform member, such that the at least one surface portion is notvisible through the indicator when the indicator is at the firsttemperature and is visible through the indicator when the indicator isat the second temperature.

The preform may also include an indicium, such as indicium 64 and 82,positioned on at least one of the surface portion of the frame member,the surface portion of the preform member, a surface portion of theindicator, or disposed within the indicator, the indicium not beingvisible through the indicator when the indicator is at the firsttemperature and being visible through the indicator when the indicatoris at the second temperature. The surface portion of the frame orpreform member can at least partially define a recess formed in theframe member or preform member.

Generally, one way of improving the materials used to form a preform isto add fillers that enhance material properties. However, theseadditives often prevent the material from becoming substantiallytranslucent at forming temperatures. There is, therefore, a need for anindicator to allow the user to know when the material is ready to form.Having an indicator allows the user to ensure that a high qualityimmobilization device can be produced in a minimum amount of time.

Referring specifically to FIG. 1, an embodiment of a preform is shownschematically as preform 1. The preform 1 includes a preform member 10and an indicator 12 that is associated with the preform member 10. Thepreform 1 is configured to be formed into an immobilizer for use with apatient and is exposed to a first temperature and an elevated secondtemperature. At the first temperature, the preform member 10 isrelatively rigid and the preform member 10 and indicator 12 are opaque.At the second temperature, the preform member 10 is less rigid and canbe molded, remaining opaque, while the indicator 12 is relativelytranslucent with respect to the preform member 10. The translucentindicator 12 provides a visual indication as to the readiness of thepreform 1 to be formed into the immobilizer. When the preform 1 iscooled from the second temperature, the indicator 12 turns fromtranslucent to opaque, thereby providing visual indication of thecompletion of forming the immobilizer. The indicator may turn opaqueprior to the material being cooled to room temperature. Therefore, theindicator may indicate that the immobilizer is approaching readiness tobe removed from the patient and that it will be ready soon when itreaches room temperature. Accordingly, the use of the indicator uponcooling is optional.

The indicator 12 is associated with the preform member 10 such that theindicator 12 is exposed to the first and second temperaturesconcurrently or substantially simultaneously as the preform member 10.The indicator 12 may be associated by being detached from and locatedproximal to the preform member 10, coupled to the preform member 10,attached to the preform member 10, positioned on a surface of thepreform member 10, disposed within the preform member 10, etc. Otherassociations between the indicator 12 and the preform member 10 foreffectuating the invention will be understood by one of skill in the artfrom the description herein.

FIGS. 2 and 3 are depictions of various embodiments in which a preformmember of a preform, illustrated as preform member 20, can be molded foruse as patient immobilization devices. The preform member 20 may be usedto form around various parts of a patient's anatomy. As depicted in FIG.2, the preform member 20 is molded over the head portion of a patient.In FIG. 3, the preform member 20 is molded around an arm of a patient,thereby forming a cast or splint 22. The preform member 20 may be formedaround the shoulders of a patient, the chest of a patient, the waist ofa patient, the legs of a patient, etc. Other parts of a patient'sanatomy around which the preform member 20 may be formed will beunderstood by one of skill in the art from the description herein.Additionally, the immobilization device formed from a preform accordingto this invention may be used for applications other than patientimmobilization as well. For example, an immobilization device accordingto this invention can be used for manufacturing processes, constructionstructures, artistic creations, and a wide variety of other uses.

Referring next to FIG. 4, a preform member 20 formed from thermoplasticmaterial and a filler material is shown. In one embodiment, thethermoplastic material includes a Polycaprolactone-based (PCL) lowtemperature thermoplastic.

Polycaprolactone (PCL) based low temperature thermoplastics are suitablefor use in a wide range of medical applications such as splinting,casting and molding for applications in Radiation Therapy andOrthopedics. The material is typically heated in a water bath or in anoven or by other application of heating energy to its melting point andis then formed around the patient's anatomy to make a custom formeddevice. The material is optionally partially cross-linked prior toheating. Such partial cross-linking improves the usability of thepreform member.

One feature of such thermoplastic materials is that in their unfilledform, they change from a milky white color to substantially translucentwhen heated to their melting point (approximately 140° F./60° C.). Suchunfilled material can be used as an indicator that the material is readyto be formed to the patient's anatomy. This can work much like the“pop-up timer” on a supermarket turkey, letting the user know that the“cooking” is complete.

It is contemplated that the preform member 20 may be formed frommultiple thermoplastic materials and/or a combination of thermoplasticmaterials and non-thermoplastic materials. Also, materials other thanthermoplastic materials can be used to form preform member 20, but suchother materials are preferably selected from materials that arerelatively rigid at a first temperature and relatively less rigid, orformable, at an elevated second temperature.

The preform member 20 additionally includes at least one filler materialtogether with the thermoplastic base material. In order to improve thephysical performance of the PCL material (i.e. stiffness and strength)as well as for aesthetic reasons, it is often desirable to add fillersto these materials. Fillers can include, but are not limited to,materials such as talc, aramid (KEVLAR®), dyes, nanoparticles, carbonfiber, fiberglass, polyurethane, fumed silica, high stiffness additives,etc.

Additionally, a thermochromic dye is optionally added to the basematerial or to the frame. For such a dye, a temperature can be selectedthat is near, above or below the softening temperature of the basematerial. Also, the dimensions of the base material and temperaturecharacteristics of such a dye can be selected such that a temperaturechange of the surface of the base material would match the actual coretemperature of the base material.

While these fillers impart desirable characteristics to the preform,they keep the materials from turning clear or translucent when heated toa molding temperature. Hence, preform members formed from filledmaterial do not provide a visible indication of when the material isready to be molded.

Referring next to FIG. 5, an embodiment of a preform 2 is shown. Thepreform 2 includes the preform member 20 that is positioned within aframe member 24. In many applications the PCL thermoplastic preformmember 20 is mounted to a rigid thermoplastic (TP) frame member 24(typically formed from ABS or another suitable material). The framemember 24 is preferably formed from a material that does not soften whenheated to 140 F (i.e., approximately the second temperature at which thepreform member 20 can be molded), the melting point of PCL. This allowsthe assembly (i.e., preform 2) to be mounted to various other devices.

At FIGS. 6A and 6B, an embodiment of a preform 3 with the preform member20 and an indicator 26 associated with the preform member 20 is shown.The indicator 26 may be formed from a thermoplastic material, such asPCL-based material. In one embodiment, the indicator 26 is formed withno filler material or at least less filler material than that of thepreform member 20.

As depicted in FIG. 6B, the indicator 26 may be formed of a materialsuch that the indicator 26 becomes translucent with respect to thepreform member 20 when the indicator 26 is heated to the secondtemperature. In order to take advantage of the characteristics of thefilled materials in the preform member 20 as discussed above withrespect to FIG. 4, while providing visual feedback to the user regardingthe readiness of the preform for forming an immobilization device, thepreform preferably includes a section of unfilled material (i.e., theindicator 26 in the embodiment illustrated in FIGS. 6A and 6B) within adevice (i.e., preform 3 in the embodiment illustrated in FIGS. 6A and6B) constructed primarily of filled materials (i.e., the preform member20 in the embodiment illustrated in FIGS. 6A and 6B).

As used herein, the term “unfilled” and “unfilled material” refers to amaterial that is less filled (as compared to the remainder of thepreform member 20 for example) such that the unfilled material becomesmore translucent as compared to the remainder of the preform member 20when heated to the second temperature. This unfilled section allows theuser to easily determine when the device (e.g., preform 3) has reachedthe melting temperature (e.g., the second temperature).

The section of unfilled material can be strategically placed such thatit does not negatively affect the beneficial properties of the filledmaterial. For example, the unfilled material that serves as an indicatorcan be placed in locations where strength or stiffness is lessimportant. In fact, a combination of filled and unfilled sections may beemployed to impart beneficial properties such as selective reinforcementcombined with the ability to determine molding readiness.

It is desirable that the section of unfilled material not indicate thatthe material is ready until the filled material reaches or approachesits melting temperature. Several strategies can be followed to achievethis result. For example, the section of unfilled material can be madeof a size, volume or thickness on the order of magnitude of that of thesurrounding material so that it has a similar mass and heat absorption.In other words, the properties of the indicator in connection with thetiming for reaching a target temperature such as its melting temperatureis preferably matched with the corresponding properties of the filledmaterial. By doing so, the indicator will accurately reflect when thefilled portion is ready for molding. If the same base material is usedfor the filled and unfilled portions, the primary variables will includethe respective sizes of the filled and unfilled portions (e.g., theirrespective thicknesses). If the base materials for the filled andunfilled portions are different, then the variables will also includethe respective properties of the base materials and how they may impacttiming for readiness for molding or forming.

The unfilled elements of the embodiment shown in FIGS. 6A and 6B can beof virtually any shape as long as the fact that they become clear (orbecome at least partially translucent as compared to the preform member20 and/or devices 1, 2, 3) is easy to visualize by the user. Viableshapes include but are not limited to squares, rectangles, circles,ovals, hexagons, strips, aesthetically desirable shapes,source-identifiers, and so forth. The unfilled elements may beperforated or not perforated. In an embodiment, the indicator 26 (i.e.,unfilled element) is formed into the shape of an alphanumeric character.In one embodiment, the indicator 26 is of a color that is different thana color of the preform member 20 and/or other components of the preform(1,2,3) at the first temperature, the second temperature, or both, so asto provide sufficient visual indication as to the readiness of thepreform to be molded and/or the location of the indicator.

FIGS. 6A and 6B illustrate the contrast between a filled portion of apreform (such as preform member 20 of preform 3) and an unfilled portionof a preform (such as indicator 26 of preform 3). In a first conditionwhen the preform 3 has not been heated (such as when it is at an ambientor room temperature), there is a smaller degree of contrast between theappearances of preform member 20 and indicator 26. For example, althoughthere may or may not be a difference in the colors of the preform member20 and indicator 26, preform member 20 and indicator 26 may have thesimilar or same degree of transparency or opaqueness.

In a second condition when the preform 3 has been heated (such as whenit is exposed to heat by heated fluid or another heat source), there isa larger degree of contrast between the appearances of preform member 20and indicator 26. For example, preform member 20 and indicator 26 willhave a degree of transparency or opaqueness. In one embodiment, preformmember 20 may be partially or completely opaque and indicator 26 may bepartially or completely translucent, thus increasing the contrast in theappearance of the preform member 20 and indicator 26 at a secondcondition of elevated temperature.

Referring next to FIGS. 7-9D, various shapes, sizes, and positions ofindicators positioned on a preform 4 are depicted. Each embodiment ofthe preform 4 includes a preform member 30 substantially as describedwith respect to preform member 20 and a frame member 32 substantially asdescribed with respect to frame member 24. The preform 4 may include oneindicator or a plurality of indicators.

As depicted in FIG. 7, indicators 34 are coupled to the frame member 32.The indicators 34 are positioned on the surface of the frame member 32and may be positioned within recesses formed in the frame member 32. Inone embodiment, the frame member 32 defines one or more apertures (notshown) and the indicators 34 are positioned to traverse the aperture(s).

In FIG. 8, indicators 36 are coupled to the preform member 30. Theindicators 36 may be positioned on the surface of the preform member 30.In one embodiment, the indicators 36 are positioned within recessesformed on the preform member 30 as will be described with respect toFIGS. 10A-10C.

In one preferred embodiment, at least one unfilled section of materialis butt-welded or otherwise directly connected to a filled section ofmaterial. The unfilled material can be placed in any position and can bestrategically positioned to maximize the benefits of the filledmaterial. For example, FIG. 9A shows one preferred embodiment in whichthe unfilled material (i.e., indicator 38 in the illustrated embodiment)is placed at the bottom of a Radiation Therapy Patient Positioning mask.The indicator 38 may extend fully or partially across the width of thepreform member 30. In an alternative embodiment (not shown), theindicator 38 may extend vertically across the preform member 30. Othersuitable orientations and extensions of the indicator 38 with respect tothe embodiment depicted in FIG. 9A will be understood by one of skill inthe art from the description herein.

Alternatively, the clear or unfilled material 40 can be embedded in thesurrounding material 30 such that it must heat up along with thesurrounding material (see, for example, the embodiment illustrated inFIG. 9B, in which an indicator of unfilled material 40 is optionallypositioned such that it is partially or completely surrounded by thefilled material 30).

The unfilled material 40 may also be solid (not perforated) while thefilled material 30 is perforated so that the unfilled material 40 areastill has higher heat capacity. In this way, the indicator can beconfigured such that it will arrive at an elevated target temperatureafter the filled material to ensure readiness of the unfilled materialfor forming.

An additional strategy is to embed the unfilled material 42 in the framemember 32 of the device 4 (see, for example, the embodiment illustratedin FIG. 9C, in which an indicator of unfilled material 42 is optionallypositioned such that it is partially or completely surrounded by theframe member 32).

These strategies ensure that the unfilled material 34, 36, 38, 40, 42,44 will not heat up more quickly than the filled material 30 and henceturn clear too early.

As described with respect to FIG. 5, the frame member 32 does not softenwhen heated to the second temperature. In these instances, thethermoplastic frame member 32 can have a section of unfilled PCLmaterial 42 embedded in it as shown in FIG. 9C. This is a preferredembodiment as it is surrounded by a solid polymer, slowing down the heattransfer to the section. In this way, it is the last part of the systemto reach molding temperature and ensures that the unfilled preformmember has reached the necessary temperature for molding and forming. Insome cases, there may be portions of the device (e.g., the frame) thathave not reached the optimum temperature (e.g., thicker sections, ribs).

In another exemplary embodiment, the filled 30 and unfilled 44 sectionsof PCL are arranged substantially similar to the arrangement shown inFIG. 9D. An arrangement of this nature maximizes the effects of therigid filled PCL 30 by placing it such that the filled PCL 30 willcreate a rigid mask. The areas of unfilled PCL 44 provide feedback tothe user when the mask has reached its melting temperature.

Referring to FIGS. 10A-10C, various arrangements of an indicator 52being associated with a preform member 50 are shown. The preform member50 and indicator 52 are substantially as described with respect topreform member 20 and indicator 26. FIG. 10A depicts the indicator 52associated with, but not directly or indirectly coupled to, the preformmember 50. In one embodiment, the indicator 52 of FIG. 10A is positionedin or near an apparatus for heating the preform member 50 and isphysically separate from the preform member 50 (e.g., installed in abath tank).

FIG. 10B depicts the indicator 52 positioned on a surface portion 54 onthe preform member 50. As depicted, the surface portion 54 of thepreform member 50 optionally partially defines a recess formed in thepreform member 50, such that the indicator 52 extends partially throughthe thickness of the preform member 50. In FIG. 10C, the preform member50 has an aperture 56 and the indicator 52 is positioned to traverse theaperture. Other suitable arrangements will be understood by one of skillin the art from the description herein.

FIGS. 11A and 11B depict an indicator 62 positioned on a frame member 60according to aspects of the invention. Alternatively, the indicator 62may be positioned on the surface of a preform member or other componentsof a preform. The indicator 62 functions substantially as described withrespect to indicator 26. At FIG. 11A, the indicator 62 has not beenheated to the second temperature and is thus opaque with respect to theframe member 60. At FIG. 11B, however, the indicator 62 has been heatedto the second temperature and is translucent with respect to the framemember 60.

According to embodiments of the invention, an indicium 64 may bepositioned such that the indicium 64 is not visible when the indicator62 is at the first temperature and is visible through the indicator 62when the indicator 62 is at the second temperature. The indicium 64 mayinclude, for example, text (such as “READY” shown in FIG. 11B), marks,symbols, a color(s), or any combination thereof. As depicted in FIG.11B, the indicium 64 is positioned on a surface of the frame member 60.The indicium 64 may optionally be positioned on a surface of theindicator 62, disposed within the indicator 62, positioned on a surfaceof a preform member, etc.

FIGS. 12A-12C depict various steps in a process for disposing anindicium 82 within an indicator 72 according to aspects of theinvention. At FIG. 12A, a preform member 70 is shown. The preform member70 may be of various thicknesses. In an embodiment, the preform member70 is between about 1.6 mm thick to about 6.4 mm thick. Defined in thepreform member 70 is an aperture 74. A bottom portion 76 of an indicator72 at least partially traverses the aperture 74 and extends at leastpartially across the thickness of the preform member 70. In oneembodiment, the bottom portion 76 is about one-half of the thickness ofthe preform member 70.

At FIG. 12B, an indicium 82 is disposed on a top surface of the bottomportion 76 of the indicator 72. The indicium 82 is substantially asdescribed with respect to indicium 64. The indicium 82 may be disposedby printing, placing, etching, laminating, etc., and may be sopositioned before or after the indicator is associated with the preform.Other suitable methods to dispose the indicium 82 will be understood byone of skill in the art from the description herein.

At FIG. 12C, a top portion 78 of the indicator 72 is disposed over theindicium 82. In one embodiment, the top portion 78 is of a thicknessabout one-half the thickness of the preform member 70. The indicium 82may be laminated or otherwise applied to the top portion 78 as opposedto or in addition to the bottom portion 76. The top portion 78 isdisposed within the aperture 72 of the preform member 70, therebysubstantially traversing the aperture 72.

Methods for forming a preform described above into an immobilizer foruse with a patient are now described in accordance with embodiments ofthe invention. A preform at a first temperature is used. The preformincludes a preform member that is formed from thermoplastic materialsand filler materials. The preform member is substantially or completelyopaque at the first temperature and a second elevated temperature. Thepreform member is relatively rigid at the first temperature and can beformed at the second temperature. The preform also includes anindicator. The indicator has an appearance at the first temperature anda different appearance at the second temperature, wherein the indicatorprovides a visual indication of readiness to form the preform into theimmobilizer upon heating the preform member to the second temperature atwhich the indicator has the different appearance. For example, theindicator is optionally substantially or completely opaque at the firsttemperature and substantially or completely translucent as compared tothe preform member at the second temperature. At the second temperature,the indicator provides visual indication of the readiness to form thepreform into the immobilizer by virtue of a contrast in the appearanceof the indicator as compared to its appearance before reaching thesecond temperature and/or as compared to the appearance of the preformmember.

First, the preform with the preform member and indicator is heated tothe second temperature. The second temperature is preferably atemperature at which the preform member can be molded and the indicatoris partially or completely translucent. The preform may be heated in abath, oven, etc., by exposure to heat from a heat source such as heatedliquid or gaseous fluid or other means for heating. Other suitablemethods and apparatus for heating the preform will be understood by oneof skill in the art from the description herein.

The indicator is then monitored while the preform is being heated fromthe first temperature to the second temperature. Once the indicatorbecomes translucent or otherwise adopts a different appearance such asby thermochromic dye or other color indicators, the preform member hasreached the second temperature and as such can be molded. The indicatorthus indicates readiness for further processing without requiringfurther delay.

The heating of the preform is then terminated after the indicatorbecomes translucent. Once the heating is terminated, the preform/preformmember is removed from the heating apparatus and formed over a portionof a patient's anatomy. Because the indicator indicates readinesswithout requiring further processing delay, beneficial time savings canbe achieved. For example, the preform can be removed from the heatsource as soon as it is ready and without further delay, thus reducingthe time for preparing the preform for forming, accelerating theavailability of the heating apparatus (such as a water bath) to processmore preforms, reducing the time a patient may need to wait before thepreform is ready for forming, and shortening the time that equipment(such as medical imaging equipment) is used for a particular patient.

Once the preform is formed over a portion of a patient's anatomy, theindicator may be monitored again. In one embodiment, the indicatorbecomes substantially or completely opaque again when the preform coolsfrom the second temperature. In such embodiments, when the indicator isopaque, the indicator provides visual indication that the preform memberhas transitioned back to being relatively rigid and can no longer bemolded.

The forming of the preform into the immobilizer may then be terminatedwhen, or soon after, the indicator becomes opaque. In some embodiments,the indicator becoming opaque does not necessarily mean that the maskcan be removed. It is, however, an optional feature that turning opaqueis one indicator that the preform is nearing the point when it can beremoved.

Because the indicator indicates completion of forming without requiringfurther processing delay, beneficial time savings can also be achieved.For example, the preform can be removed from the patient as soon as itis ready and without further delay, thus reducing the time for preparingthe immobilizer, accelerating the availability of the facilities inwhich the immobilizer is formed, reducing the time a patient may need towait before the immobilizer is completed, and shortening the time thatequipment (such as medical imaging equipment) is used for a particularpatient.

The aforementioned steps for forming a preform into an immobilizer foruse with a patient are exemplary and not exclusive. One of skill in theart will understand other suitable forming methods according to aspectsof the invention from the description herein. Also, subsets of the stepsmay be performed, and the steps may be completed in various orders.

While preferred embodiments of the invention have been shown anddescribed herein, it will be understood that such embodiments areprovided by way of example only. Numerous variations, changes andsubstitutions will occur to those skilled in the art without departingfrom the spirit of the invention. Accordingly, it is intended that theappended claims cover all such variations as fall within the spirit andscope of the invention.

What is claimed:
 1. An immobilization device having multiple sectionsformed from a low temperature thermoplastic, the immobilization devicecomprising: at least one preform section that does not becometranslucent when heated to an elevated temperature, the section beingformed from a low temperature thermoplastic, the at least one preformsection being more rigid at a non-elevated temperature and beingmoldable at the elevated temperature; and at least one indicator sectionthat becomes translucent when heated to the elevated temperature atwhich the at least one preform section is moldable, thereby providing avisual indication of readiness for forming the at least one preformsection and a visual indication for terminating the forming of the atleast one preform section.
 2. The immobilization device of claim 1 inwhich the at least one indicator section has a size greater than 1 mm̂2.3. The immobilization device of claim 1 in which an edge of the at leastpreform section is attached to an edge of the at least one indicatorsection.
 4. The immobilization device of claim 1 wherein at least onepreform section is perforated.
 5. The immobilization device of claim 1wherein at least one indicator section is perforated.
 6. Theimmobilization device of claim 1, further comprising a frame, said framehaving at least one indicator section embedded within it.
 7. Theimmobilization device of claim 1, wherein the low temperaturethermoplastic is a polycaprolactone based low temperature thermoplastic.8. The immobilization device of claim 1, wherein the at least onepreform section that does not become translucent further comprises atleast one filler material.
 9. A method of preparing a preform to beformed into an immobilizer for a patient, the method comprising: heatinga preform member of the preform from a first temperature at which thepreform member is relatively rigid to a second temperature at which thepreform member can be molded; monitoring an indicator associated withthe preform member while heating the preform member, the indicator beingformed from a thermoplastic material, the indicator being opaque at thefirst temperature and translucent at the second temperature, the methodfurther comprising terminating the heating of the preform member afterthe indicator becomes translucent, thereby providing a visual indicationof readiness to form the preform into the immobilizer.
 10. The method ofclaim 9, wherein the low temperature thermoplastic of the preform memberis a polycaprolactone based low temperature thermoplastic.
 11. Themethod of claim 9, wherein the thermoplastic material that is opaque orsubstantially opaque at the first and second temperatures furthercomprises a filler material.
 12. The method of claim 9, wherein thethermoplastic material of the preform member includes polycaprolactone.13. The immobilization device of claim 1, wherein the low-temperaturethermoplastic material does not contain a filler.
 14. An immobilizationdevice comprising: a preform formed from a low temperaturethermoplastic, the preform being moldable at an elevated temperature,the preform having multiple sections, the preform comprising: at least afirst section of the preform that becomes translucent when heated to theelevated temperature, such that the first section provides a visualindication of the preform being moldable a frame, the frame being rigidat a non-elevated temperature and at the elevated temperature.
 15. Theimmobilization device of claim 14, further comprising a second sectionof the preform, the second section of the preform having a fillermaterial,
 16. The immobilization device of claim 15, wherein the firstsection of the preform has less of the filler material than the secondsection of the preform.
 17. A preform configured to be formed into animmobilizer for a patient, the preform comprising: a preform member thatis relatively rigid at a first temperature and that is moldable at asecond temperature that is elevated relative to the first temperature,the preform member being formed from a thermoplastic material and beingopaque or substantially opaque at the first temperature and the secondtemperature; an indicator associated with the preform member andpositioned to be monitored while heating the preform member, theindicator being formed from a thermoplastic material, the indicatorbeing opaque at the first temperature and translucent at the secondtemperature; wherein the indicator is configured to provide a visualindication of readiness to form the preform into the immobilizer whenthe indicator becomes translucent.
 18. The preform of claim 17, whereinthe low temperature thermoplastic of the preform member is apolycaprolactone based low temperature thermoplastic.
 19. The preform ofclaim 17, wherein the thermoplastic material that is opaque orsubstantially opaque at the first and second temperatures furthercomprises a filler material.